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Submission #25398

# Submission time Handle Problem Language Result Execution time Memory
25398 2017-06-22T04:17:08 Z 김현수(#1065) Watching (JOI13_watching) C++11
100 / 100
 506 ms 33472 KB 
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll inf = 1e18;
ll n, x[2005], a, b, na[2005], nb[2005];
ll dt[2005][2005];

bool can (ll P) {
	for(ll i=1;i<=n;i++) {
		na[i] = lower_bound(x+1, x+1+n, x[i]+P) - x - 1;
		nb[i] = lower_bound(x+1, x+1+n, x[i]+2*P) - x - 1;
		for(ll j=0;j<=i;j++) dt[i][j] = inf;
	}
	for(ll i=1;i<=n;i++) {
		for(ll j=0;j<i;j++) {
			dt[na[i]][j] = min(dt[na[i]][j], dt[i-1][j] + 1);
			dt[nb[i]][j+1] = min(dt[nb[i]][j+1], dt[i-1][j]);
		}
	}
	for(ll i=0;i<=b;i++) if(dt[n][i] <= a) return true;
	return false;
}

int main()
{
	scanf("%lld%lld%lld",&n,&a,&b);
	if(a + b >= n) {puts("1"); return 0;}
	for(ll i=1;i<=n;i++) {
		scanf("%lld",&x[i]);
	}
	sort(x+1, x+1+n);
	ll S = 1, E = inf;
	while(S<E) {
		ll M = (S+E)/2;
		can(M) ? E = M : S = M+1;
	}
	printf("%lld\n",S);
}

Compilation message

watching.cpp: In function 'int main()':
watching.cpp:26:32: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%lld%lld%lld",&n,&a,&b);
                                ^
watching.cpp:29:22: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%lld",&x[i]);
                      ^

Subtask #1
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 33472 KB Output is correct
2 Correct 0 ms 33472 KB Output is correct
3 Correct 0 ms 33472 KB Output is correct
4 Correct 0 ms 33472 KB Output is correct
5 Correct 0 ms 33472 KB Output is correct
6 Correct 0 ms 33472 KB Output is correct
7 Correct 0 ms 33472 KB Output is correct
8 Correct 0 ms 33472 KB Output is correct
9 Correct 0 ms 33472 KB Output is correct
10 Correct 0 ms 33472 KB Output is correct
11 Correct 0 ms 33472 KB Output is correct
12 Correct 0 ms 33472 KB Output is correct
13 Correct 0 ms 33472 KB Output is correct
14 Correct 0 ms 33472 KB Output is correct
15 Correct 0 ms 33472 KB Output is correct

Subtask #2
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 469 ms 33472 KB Output is correct
2 Correct 0 ms 33472 KB Output is correct
3 Correct 0 ms 33472 KB Output is correct
4 Correct 0 ms 33472 KB Output is correct
5 Correct 0 ms 33472 KB Output is correct
6 Correct 0 ms 33472 KB Output is correct
7 Correct 466 ms 33472 KB Output is correct
8 Correct 489 ms 33472 KB Output is correct
9 Correct 496 ms 33472 KB Output is correct
10 Correct 459 ms 33472 KB Output is correct
11 Correct 479 ms 33472 KB Output is correct
12 Correct 493 ms 33472 KB Output is correct
13 Correct 456 ms 33472 KB Output is correct
14 Correct 506 ms 33472 KB Output is correct
15 Correct 493 ms 33472 KB Output is correct